Mineral Veins 
75 
the reader to comprehend the labours of the padres, the trap¬ 
pers, and the explorers, some account of whose doings is pre¬ 
sented in the following chapters/ 
’ In connection with the subject of erosion and corrasion the reader is advised 
to study the following works, which are the standards : The Exploration of the 
Colorado of the West, and the Geology of the Uinta Mountains, by J. W. Powell; 
The Hetiry Mountains, by G. K. Gilbert ; The Geology of the High Plateaus of 
Utah, and The Tertiary History of the Grand Canyon District, by C. E. Dutton. 
